In a manufacturing process of a semiconductor device, plasma processing such as etching processing has been conventionally performed on a substrate such as a semiconductor wafer using a plasma and, for instance, formation of a stacked pattern structure having layers containing a metal such as titanium (Ti) and tungsten (W) has been conducted with the use of plasma etching. Note that as a technology to perform etching on tungsten (W), there has been known one that uses a gas obtained by mixing a gas containing fluorine atoms, a gas containing chlorine atoms, and an oxygen gas, or the like, for example (refer to Reference 1, for instance).
When the pattern structure containing the metal such as titanium (Ti) and tungsten (W) is formed by using the plasma etching as described above, a deposit (deposited substance) containing the metal sometimes remains on a sidewall of the pattern. If formation of CVD film is carried out in a post-process in a state where the deposit containing the metal still remains, the deposit containing the metal sometimes becomes a cause (nucleus) of abnormal growth. For this reason, there is a need to remove the deposit containing the metal.
As a method of removing a deposit containing a metal generated at a time of performing etching on a metal film, a method using wet cleaning has been known. Further, there has been known a method of removing a deposit containing a metal using heating processing or gas processing using a fluorine-containing gas (refer to Reference 2, for instance).
Reference 1: JP-A 10-178014 (KOKAI)
Reference 2: JP-A 2000-082693 (KOKAI)
Among the above-described methods of removing the deposit containing the metal generated at the time of performing etching on the metal film, the method using the wet cleaning has a problem that a pattern collapse may occur.
Meanwhile, the method with the use of the heating processing or the gas processing using the fluorine-containing gas has a problem that a deposit capable of being removed is limited, and thus the removal cannot be conducted depending on deposits. Further, there is a problem that if a deposit which cannot be removed by the method with the use of the heating processing or the gas processing using the fluorine-containing gas is tried to be removed using a plasma, a metal layer included in a pattern structure is etched (side-etched), resulting in that the pattern becomes thin.